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07 February 2010

Even if you're not around here (Washington DC area), I gather several folks have heard about our weather. Having been reminded by JG that not everybody has seen snow, I caught some video of the flakes in action. And being reminded of Nakaya's work on ice crystal types, I have a still that attempts to catch a few snow crystals.

Snow crystals on my coat sleeve:

Be sure to click on that to see full size. One thing to notice, aside from the fact that many have already melted, is that most are little needles. Some of the needles have clumped together, like the one near the loose thread in the middle of the photo. If you look carefully, you can see that the needles have little balls on their ends. The little balls are liquid water cloud droplets that froze instantly onto the needles as the needles fell through the cloud. It's called riming, even as it happens to a single snow crystal. (Riming is a serious hazard for aircraft taking off or landing in near-freezing conditions.)

Thanks for the snow images. I was watching rain again this weekend, and I was suprised by how many of the fine mist droplets were going upward. For obvious reasons, I did not try to capture it with my video camera.jg

Interesting - this afternoon's snow had the classic flat flakes singly and in clusters. Tonight's snow is more granular. Offices closed again tomorrow, so more snow-watching ahead (along with getting to the work I took/sent home).

I have almost a snow story. Where I live we may get hail once or twice a year. Yesterday, I was starting an after school astronomy presentation for a middle school astronomy club and it started to hail. Pow! The students bolted from their seats and ran outside. I would have dismissed them, but before I could be so magnanimous, they were outside running, stomping, and gathering what they could. I encourage Bob to continue this and related precipitation topics.jg

Deech56:You understand why snow might have been a little on my mind :-) As a Buffalo person, you've probably seen something I always was amused by -- lake effect snowfall with no clouds in the sky. Always very powdery snow and usually a nice sun halo.

I've kind of burned out on snow observing, so haven't been out to see what the flakes are like this time. With the 15-25 m/s (30-50 mph) wind gusts, it's pretty hard to see snowflakes individually anyhow.

jg:You can do your mist videos the way I did the snow videos -- sit inside warm and dry and film through the kitchen window. I concede that this might lack something for precision or authenticity, but it's a lot safer for the camera.

Hail is interesting stuff. I'll make a note about putting together a post about it. Probably closer to my own hail season -- April or so. First day I was delivering newspapers we had a hailstorm.

Welcome

I'll be trying what seems to be an unusual approach in blogs -- writing to be inclusive of students in middle school and jr. high*, as well as teachers and parents (whether for their own information or to help their children). To that end, comments will have to pass a stricter standard than I'd apply for an all-comers site. It shouldn't be onerous, just keep to the topic and use clean language.

I expect it to be fun for all, however, as you really can get quite far in understanding the world, even climate, by understanding this sort of fundamental. If I get too much less fundamental, let me know where I went astray.

* Ok, I concede that not many middle school students will get everything. Even a fair number of adults will find some parts hard to follow. Still, some middle school kids will have fun. And almost everyone will follow a number of posts just fine.

Please see the comment policy for details. And the link policy for details about that. The latter is more open than you might expect.

About Me

In my day job I work on the oceanography, meteorology, climatology, glaciology end of my science interests, but I'm interested in everything, science or not. So I've also been on stage in a production of Comedy of Errors, run an ultramarathon, and been to Epidaurus, Greece, to see a production of Euripides' Iphigenia among the Taurians
Prior to starting the current job, I was a post-doc in oceanography in the UCAR ocean modelling program, and earned my doctorate from the Department of the Geophysical Sciences at the University of Chicago (1989). My undergraduate degree involved Applied Math, Engineering, Astrophysics, and Glaciology.
Of course I don't speak for my employer, whoever that may be.